BM1000 Lecture Notes - Lecture 28: Growth Medium, Catalase, Toothpick
Document Summary
Diagnosis & treatment depends of correct id of pathogens. Samples must be taken from patients, transported to lab, cultured & id"d. Need to be familiar with normal flora of different sites of body. Can rule these out following culture & id. Contain substances that favour growth of one microbe and/or inhibits others. Cetrimide main ingredient of dettol: aeruginosa produces a number of iron chelators. Due to the ph indicators responding to acid production. Creates visible changes in the appearance of bacterial colonies. Different bacteria will use the ingredients of a given medium in different ways. Exotoxins called haemolysins cause lysis of the red blood cells. The type of haemolysis is useful for id. Beta haemolysins completely lyse the red blood cells. Alpha haemolysis refers to the partial lysis of rbc"s. No haemolysis, sometimes called gamma haemolysis results in no change of the medium. the. Bile salts, crystal violet dye to inhibit gram-positives.
